Filter bag cleaning system

ABSTRACT

A baghouse cleaning system comprises an elongated air accumulator configured to retain pressurized air and extend over a row of filter bags. An elongated air tube extends along the air accumulator and venturis extend from the air tube. The venturis blow pressurized air streams down into the filter bags to remove particles attached to an outside filter bag surface. A valve fluidly couples the air accumulator to the air tube and an actuator is configured to move the cleaning arm linearly over different rows of the filter bags. A sensor may determine when the filter bags need to be cleaned based on a measured air pressure. A controller can actuate the cleaning arm to clean the filter bags based on preprogrammed cleaning patterns, the amount of measured air pressure, and/or other detected environmental conditions.

BACKGROUND

A facility may launch particulates into the air while manufacturing orprocessing products. The particulates may comprise dust, wood, metal,other organic or inorganic materials, or the like, or any combinationthereof. Baghouses are used for removing the particulates from the air.A fan pulls the contaminated air from the facility into the baghouse andthrough filter bags. An outside surface of the filter bags collect theparticulates while the filtered air continues up through the filter bagsand out a clean air chamber of the baghouse to the fan.

A cleaning system removes the particulates that have accumulated on theoutside surface of the filter bags. Pressurized air is shot down into aninside center section of the filter bags. The pressurized air brieflyreverses the air flow through the filter bags causing the filter bags toslightly expand and shake off the particulates that accumulated on theoutside filter bag surface. The particulates fall down into a collectionchamber and are transported to a waste facility.

Baghouse cleaning systems are generally complex, expensive to installand operate, and inefficient. For example, circular cleaning systems mayrotate in a circle around a center location inside of a round baghousestructure. The cleaning system may clean different subsections of filterbags at one time and then rotate to next subsection. Circular baghousecleaning systems are relatively complex and use a complex series oftubes and valves to blow air into the individual filter bags. Thecomplexity of the cleaning system adds to the overall cost andmaintenance of the baghouse.

Round baghouses may also underutilize overall cleaning capacity. Forexample, a square or rectangular space is typically allocated within ornext to the facility for the baghouse structure. However, the circulararrangement of the filter bags and cleaning system do not utilize thesquared corner sections of the allocated baghouse space. The circularbaghouse has reduced air filtering capacity since only a circularsubportion of the available space is used for retaining filter bags.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a perspective isolated view for a portion of a baghouse.

FIG. 2 depicts a partial perspective view of a filter bag cleaningsystem.

FIG. 3 depicts a top plan view of a filter bag cleaning system.

FIG. 4 depicts a side isolated view of a filter bag cleaning system.

FIG. 5 depicts a side view of an actuator for moving the filter bagcleaning system.

FIG. 6 depicts an example of an actuator.

FIG. 7 depicts an example process for controlling a filter bag cleaningsystem.

DETAILED DESCRIPTION

FIG. 1 depicts an example of a baghouse 90 comprising a frame structure102 that holds filter bags 108 vertically above a lower chamber 92.Filter bags 108 may have a circular cross-section and comprise awire-reinforced internal cage covered by a fabric with a closed bottomend and an open top end. It should be understood that other baghouseconfigurations may exist and the cleaning system described below may bemodified to operate within these other baghouse configurations.

A cleaning system 100 operates within baghouse 90 and removesparticulates 122 that may accumulate on the exterior surface of filterbags 108. Cleaning system 100 may comprise a cleaning arm 112 thatextends above the top ends of filter bags 108. Proximity sensors 104 maybe located and extend along a side of frame structure 102 having beams106. Each proximity sensor 104 may be aligned next to a different row offilter bags 108. A shaft 114 is attached at a center location ofcleaning arm 112 and causes cleaning arm 112 to move linearly between afront end 101 of frame structure 102 and a back end 103 of framestructure 102. A front end of shaft 114 is attached to a motor 110 and arear end of shaft 114 is rotatably attached to back end 103 of framestructure 102.

A fan (not shown) pulls air 120 with particulates 122 through inlet 94into lower chamber 92 below filter bags 108. In one example, air 120 maycome from a facility that generates particulates 122 during amanufacturing or service process. However, air 120 and the carriedparticulates 122 can come from any source. Baghouse 90 operates as acyclone forcing unfiltered air 120 up into and through filter bags 108.Particulates 122 are captured on an exterior surface of filter bags 108and clean filtered air 124 is drawn up through the center section offilter bags 108, through holes 118 in a support plate 116, and outthrough an outlet 98 in an upper chamber 96 of baghouse 90.

As more particulates 122 accumulate on the outside filter bag surface,less air 120 can pass through filter bags 108 reducing the overallcleaning capacity of baghouse 90. Cleaning arm 112 shoots bursts of airinto the center of filter bags 108 to remove particulates 122 attachedto the outside filter bag surface. The bursts of air reverse air flowthrough a row of filter bags 108 blowing particulates 122 off of theoutside surface and into a discharge opening 99. The air bursts may alsoslightly expand filter bags 108 outwardly away from their internal cagesfurther breaking up and shaking off particulates 122 that may haveattached and/or caked onto the filter bag outside surfaces.

FIG. 2 depicts a perspective view for cleaning system 100. A housing 130for baghouse 90 extends around support plate 116 and filter bags 108 andforms lower chamber 92 in FIG. 1. An upper housing is not shown butextends over support plate 116 and filter bags 108 and forms upperchamber 96 in FIG. 1. The open upper ends of filter bags 108 areattached around holes 118 in support plate 116. In one example, filterbags 108 and holes 118 may have circular cross-sectional shapes, but mayhave other shapes or dimensions.

Cleaning arm 112 comprises an accumulator 140 that extends across anentire row of filter bags 108. Accumulator 140 is alternatively referredto as an air header and in one example comprises a hollow beam with asquare, rectangular, or round cross-sectional shape. Of courseaccumulator 140 may comprise other shapes. A diaphragm valve 136 fluidlyconnects accumulator 140 to a blow tube 142 that extends in parallelbelow accumulator 140. A row of venturis 144 extend down from blow tube142 and are spaced apart to align over vertical centerlines for a row offilter bags 108. A flexible power track 134 contains an air tube 154that directs compressed air from an air source into accumulator 140. Acontrol line 138 in power track 134 is used by a controller 133 tocontrol when diaphragm valve 136 opens and closes thus directingcompressed air from accumulator 140 into blow tube 142 and out ofventuris 144.

A front end of shaft 114 is rotatably connected to a gear converter 160and rotatably retained by a bracket 162. Motor 110 rotates shaft 114 viagear converter 160 in either a clockwise or counter clockwise direction.An actuator 148 is held below accumulator 140 by a bracket 146 andconverts rotary motion of shaft 114 into a linear motion moving cleaningarm 112 forward or backwards along shaft 114.

Motor 110 rotates shaft 114 causing actuator 148 to move cleaning arm112 from a front row of filter bags 108, over intermediate rows offilter bags 108, until reaching a back row of filter bags 108. Afterreaching the back row of filter bags 108, motor 110 changes therotational direction of shaft 114 causing actuator 148 to move cleaningarm 112 from the back row of filter bags 108, over the intermediate rowsof filter bags 108, until reaching the front row of filter bags 108.Controller 133 can be programmed to provide any pattern for cleaningfilter bags 108 with cleaning arm 112 and will be discussed in moredetail below.

A pair of v-guide tracks 158 extend along opposite sides of plate 116.Top ends of support arms 170 support opposite lateral ends ofaccumulator 140. Bottom ends of support arms 170 attach to v-guidewheels 156 that roll on top of tracks 158. Linear movement of actuator148 along shaft 114 moves cleaning arm 112 and causes wheels 156 to rollalong tracks 158. Power track 134 bends backwards in response to linearmovement of cleaning arm 112 towards the back end of support plate 116.Power track 134 bends forward in response to linear movement of cleaningarm 112 towards the front end of support plate 116. One example powertrack 134 may be manufactured by Gleason Reel®, P.O. Box 26, 600 S.Clark Street, Mayville, Wi. 53050; www.gleasonreel.com.

A pair of pitot tubes 152A and 152B (see FIG. 3) are held by brackets150 on opposite front and back sides of accumulator 140. One example ofpitot tubes 152 are manufactured by Dwyer Instruments, Inc., 102 IndianaHwy, Michigan City, In. 46360. A back end of pitot tubes 152 are held inpower track 134. Head ends of pitot tubes 152 can be positioned overdifferent holes 118 and vertical centerlines for the different filterbags 108. For example, a front one of pitot tubes 152A may extend downfrom a front side of accumulator 140. Pitot tube 152A may be moved overone of filter bags 108 in a next forward row of filter bags prior tocleaning arm 112 moving in a forward direction over the next forward rowof filter bags. A back one of pitot tubes 152B (see FIG. 3) may extenddown from a back side of accumulator 140. Pitot tube 152B may be movedover one of the filter bags in a next rearward row of filter bags priorto cleaning arm 112 moving in a rearward direction over the nextrearward row of filter bags.

Pitot tubes 152 may determine when different filter bags 108 need to becleaned. As explained above in FIG. 1, air from a lower chamber of thebaghouse flows up and through the center hollow portion of filter bags108. Particulates in air 120 are trapped on the outside surface offilter bags 108 and filtered clean air 124 continues to pass up from thecenter portion of filter bags 108 and out through holes 118 (see FIG.1).

The amount of air passing through filter bags 108 is reduced as theparticulates continue to accumulate on the outside surface of filterbags 108. The associated amount of air pressure or air velocity withinfilter bags 108 also reduces as more particulates accumulate and cakeonto the outside surface of filter bags 108. Different filter bags 108may also accumulate different amounts of particulates. For example,filter bags 108 near inlet 94 (FIG. 1) in the lower chamber of thebaghouse may capture more particulates than filter bags further awayfrom inlet 94. Therefore, different filter bags may need differentamounts of cleaning.

Pitot tubes 152 measure the amount of air pressure or air velocity infilter bags 108. For explanation purposes, the air pressure or airvelocity measured by pitot tubes 152 will be referred to generally asair pressure. A particular filter bag 108 may be considered relativelyclean when the air pressure measured by pitot tube 152 is relativelyhigh. In this case, the row of filter bags containing the filter bagwith the high associated air pressure may not be cleaned. For example,cleaning arm 112 may pass over the row of filter bags without releasingpressurized air from accumulator 140 into blow tube 142 and out venturis144.

Cleaning arm 112 may be moved toward a next row of filter bags 108. Aparticular filter bag 108 in the next row may be considered relativelydirty when the air pressure measured by pitot tube 152 is relativelylow. In this case, the next row of filter bags containing the filter bagwith the low air pressure may be cleaned. For example, cleaning arm 112may be moved over the next row of filter bags and pressurized air may bereleased from accumulator 140 into blow tube 142 and out venturis 144.The pressurized air output from venturis 144 reverse a direction of airflow through the row of filter bags from an upward and inward directionto a downward and outward direction. The reversed air flow blowsparticulates off the outside surface of the filter bags 108 causing theparticulates to fall down into a discharge opening as explained above inFIG. 1.

Selective filter bag cleaning based on air pressure may reduce overallwear and maintenance since filter bags 108 may be cleaned less often andfewer reverse air pressure shocks may be applied to filter bags 108.Cleaning system 100 may also be more energy efficient since less energymay be needed for generating and shooting high pressure air out ofcleaning arm 112 into filter bags 108.

A junction box 132 may connect a compressed air line 164, electricalcontrol lines 166, and/or any other mechanical, electrical, or pneumaticcables or lines through power track 134 to cleaning arm 112. Junctionbox 132 may be connected to motor 110 by power and control cables 168.In one example, junction box 132 may contain a controller 133, sensors,air valves and/or any other elements needed for monitoring andcontrolling movement of cleaning arm 112 and controlling the release ofcompressed air out of venturis 144.

In another example, some or all of the electrical, mechanical, and/orpneumatic monitoring and control of cleaning arm 112, motor 110,diaphragm valve 136, and/or pitot tubes 152 may be performed remotely.For example, a computer system may be located in a control room and maymonitor and/or control cleaning system 100 via electrical or pneumaticcontrol lines 166 and air line 166.

FIG. 3 depicts a top plan view of cleaning system 100. A positionactivator 172 extends out from a first lateral end of cleaning arm 112and a position activator 178 extends out from an opposite lateral end ofcleaning arm 112. A set of proximity sensors 174A are located next tofront end 101 of frame structure 102 and a second set of proximitysensors 174B are located near back end 103 of frame structure 102. Aseries of proximity sensors 104 are located on a sensor mount 176 thatextends along a side of frame structure 102. Each proximity sensor 104is co-linearly aligned with a row of holes 118 in plate 116 and theattached filter bags 108. Wires (not shown) are connected from proximitysensors 174 and proximity sensors 104 to controller 133 located eitherin junction box 132 or located at a remote location.

Motor 110 may rotate shaft 114 in a clockwise or counter clockwisedirection. In one example clockwise rotation of shaft 114 may causeactuator 148 (FIG. 2) to move cleaning arm 112 in the rearward directionfrom front end 101 of frame 102 to back end 103 of frame 102. Pitot tube152B on the back side of accumulator 140 may pass over a next row offilter bags 108. Controller 133 may decide to clean the next row offilter bags based on the air pressure measured by pitot tube 152B.

Controller 133 detects when position activator 178 moves over proximitysensor 104 and is co-linearly aligned with the next row of filter bags.If cleaning is needed, controller 133 opens valve 136 releasing air fromaccumulator 140 into and out of blow tubes 142 and venturis 144 (FIG.2). Controller 133 continues to move cleaning arm 112 toward back end103 of frame structure 102 while cleaning different rows of filter bags108.

Controller 133 detects when position activator 172 moves acrossproximity sensors 174B indicating that the next row of filter bags 108is the last row in support plate 116. After moving over the last row offilter bags 108, controller 133 reverses motor 110 changing therotational direction of shaft 114. Actuator 148 starts moving in anopposite direction along shaft 114 moving cleaning arm 112 from back end103 of frame structure 102 toward front end 101 of support structure102.

Pitot tube 152A may be used while cleaning arm 112 moves in the forwarddirection. Controller 133 monitors the air pressure for upcoming rows offilter bags with pitot tube 152A and the location of cleaning aim 112via proximity sensors 104 and selectively cleans different associatedrows of filter bags 108. Controller 133 detects when cleaning arm 112reaches the front row of filter bags 108 when position activator 172moves across proximity sensors 174A. Controller 133 may then directmotor 110 to rotate in the opposite direction and start moving cleaningarm 112 in the rearward direction again towards back end 103 of frame102.

Only two pitot tubes 152A and 152B are shown in FIG. 3. However, anycombination of pitot tubes 152 may be used. For example, multiple pitottubes 152 may measure air pressure in multiple filter bags in the samerow. The measured air pressures may be averaged and subsequent cleaningof the next row of filter bags may be determined based on the averagemeasured air pressure. Any other type of air pressure measurement devicemay be used and any other device may be used for detecting dirty filterbags 108.

In another example, multiple pitot tubes 152 may measure air pressure inmultiple different rows of filter bags 108 at the same time. A next rowof filter bags 108 may be cleaned based on the average air pressure forthe multiple different rows. In yet another example, rows of filter bagsmay be cleaned based on a change in measured air pressure betweendifferent adjacent rows of filter bags 108.

In yet another embodiment, venturis 144 may have individual valvesfluidly controlling air flow from accumulator 140. Pitot tubes 152 maybe located above each column of filter bags 108, or above differentgroup of columns of filter bags 108. Filter bags 108 in individual rows,individual columns, and/or individual groups of rows or columns, may becleaned based on the measured air pressure.

In yet another embodiment, pitot tubes 152 may not be used or may onlybe used during certain environmental conditions. For example, controller133 may be loaded with a preprogrammed cleaning sequence. The programmedcleaning sequence may direct controller 133 to clean every other row offilter bags 108 when cleaning arm 112 is moving in the rearwarddirection from front end 101 of frame structure 102 toward back end 103of frame structure 102. The programmed cleaning sequence may directcontroller 133 to clean the other alternating rows of filter bags 108when cleaning arm 112 is moving in the forward direction from rear end103 toward front end 101 of frame structure 102. Of course, any cleaningpattern of rows and/or columns may be programmed into controller 133.

In yet another embodiment, filter bags 108 may be cleaned based ondifferent environmental conditions. One or more sensors 129 may measureany combination of environmental conditions such as air pressure, time,temperature, humidity, or the like, or any combination thereof. Based onthe sensor measurements, controller 133 may vary a speed of motor 110and/or change the cleaning pattern for cleaning arm 112.

For example, filter bags 108 may need to be cleaned more frequentlyduring certain humidity or temperature conditions. During the identifiedhumidity or temperature conditions, controller 133 may increase a speedin which cleaning arm 140 is moved over rows of filter bags, may cleaneach row of filter bags instead of every other row or filter bags,and/or may blow air from the venturis into the filter bags 108 forlonger periods of time. In another example, pitot tubes 152 are onlyused during the identified humidity or temperature condition.

FIG. 4 depicts a side view of cleaning system 100. Support plate 116 isshown supporting rows of filter bags 108 in vertical alignment. A topend of support arms 170 hold accumulator 140 above filter bags 108 andbottom ends of support arms 170 are rotatably coupled to wheels 156.Wheels 156 roll on v-tracks 158. Position activator 172 is shown locatedadjacent to proximity sensors 174A and as mentioned above are used bythe controller to determine when cleaning arm 112 has reached a frontend of the baghouse.

Power track 134 contains air hose 154 for supplying pressurized air toaccumulator 140. Pitot tube 152A is shown positioned in front of the rowof filter bags 108 currently being cleans by cleaning arm 112 and mayhave previously measured the air pressure for one of filter bags 108.Based on the measured air pressure, or based on a pre-programmedcleaning pattern, the controller may open valve 136 via control line138. Valve 136 directs pressurized air from accumulator 140 into blowtube 142 and out venturis 144 as pressurized air streams 182. Airstreams 182 reverse the air flow through filter bags 108 blowing andshaking particulates 122 off the outside surface of filter bags 108. Airstreams 182 may quickly and briefly blow filter bags 108 into anexpanded condition 192 that further crack, separate, and/or shakeadditional particulates 122 off of the outside surface of filter bags108.

Actuator 148 is shown contained within an enclosure 186 and held belowaccumulator 140 by bracket 146. Actuator 148 moves in a forward orrearward direction along shaft 114 based on a rotational direction ofshaft 114. In one example, enclosure 186 may be pressurized to keep dustfrom accumulating on actuator 148. A pressure gauge 184 may indicate theair pressure within enclosure 186.

FIG. 5 shows a side sectional view of cleaning arm 112. Accumulator 140has a square or rectangular cross-sectional shape and a hollow internalsection for storing pressurized air. Bracket 146 holds actuator 148 to abottom side of accumulator 140. Blow tube 142 has a circularcross-sectional shape and a hollow internal section for receiving thepressurized air from accumulator 140. Venturi 144 is fluidly attached toblow tube 142 and blows the pressurized air stream into the filter bags.

As mentioned above, actuator 148 may be contained within an air tightenclosure 186. Washers 194 maintain a seal between shaft 114 and aninternal chamber of enclosure 186. A valve 188 may direct pressurizedair from accumulator 140 into the internal chamber of enclosure 186. Theincreased air pressure forces particles away from the internal chamberof enclosure 186 and actuator 148. Thus, actuator 148 may be exposed toless dust and require less maintenance and cleaning.

The amount of air pressure generated in enclosure 186 can be controlledby valve 188 and measured by pressure gauge 184. In one example, valve188 is manually turned on and off. In another example, valve 188 may beelectrically controlled to turn on and off based on feedback signalsreceived from pressure gauge 184. For example, if pressure gauge 184detects a drop in air pressure, valve 188 may be turned on and increasethe air pressure within enclosure 186 to a preprogrammed level.

FIG. 6 shows actuator 148 in more detail. Actuator 148 may comprise twoblocks 200A and 200B that attach around upper and lower sides of shaft114 and are held together with screws 204. Rolling ball bearings 202 areheld in blocks 200 and trace a helix pattern along shaft 114alternatively referred to as a rolling helix. Bearings 202 contact shaft114 at an angle. When shaft 114 is rotated, bearings 202 trace out animaginary screw thread, causing actuator 148 to travel linearly alongshaft 114.

Thrust of actuator 148 along shaft 114 is determined by spring force ofsprings (not shown) that are located within blocks 200 and over screws204. The tighter screws 204 clamp together blocks 200A and 200B, thetighter the springs are compressed together and the more firmly bearings202 press against shaft 114. The tighter bearings 202 press againstshaft 144, the more thrust actuator 148 asserts against shaft 114.Actuator 148 also allows bearings 202 to slip when a thrust capacity isexceeded, thereby offering protection to motor 110 and other baghousecomponents. One example of an actuator 148 is manufactured by Zero-Max,Inc. 13200 Sixth Avenue North, Plymouth, Minn. 55441-5509;WWW.zero-max.com.

FIG. 7 depicts an example of a process that may be performed forcleaning filter bags. In operation 250, the controller may identify acleaning pattern for the filter bags. The cleaning pattern may bepre-programmed or may vary based on measured environmental conditions.For example, as mentioned above, a first cleaning pattern may comprisecleaning every other row of filter bags while the cleaning arm is movingin a rearward direction in the baghouse. The other set of alternatingrows may be cleaned as the cleaning arm travels in a forward directionin the baghouse. The controller may direct motor 100 to rotate shaft 114at a given rotational speed so that each row of filter bags is cleanedat a certain periodic rate.

Other programmed cleaning patterns may be stored in a memory and used bythe controller based on changing environmental conditions. Based on airpressure, temperature, humidity, time of day, type of particulates, orthe like, or any combination thereof, the controller may use a differentcleaning pattern. For example, particulates may accumulate faster on theoutside surface of filter bags 108 during different humidity ortemperature conditions.

The controller may dynamically select a new cleaning pattern in responseto detecting the particular humidity or temperature condition. Forexample, the new cleaning pattern may clean every row of filter bagswhile the cleaning arm is moving in the forward direction and therearward direction. Accordingly, the controller may turn on thediaphragm valve and direct air streams through the venturis each timethe cleaning arm moves over a new row of filter bags. In anotherexample, the new cleaning pattern may indicate a different speed for thecleaning arm. Accordingly, the controller may send new signals to themotor to change a rotational speed that causes the cleaning arm to cleanthe filter bags at a different rate.

In operation 252, the controller may determine if dust accumulationbased cleaning should be activated. Dust accumulation based cleaning maybe pre-programmed into the controller or may be dynamically activatedeither manually or automatically. For example, an operator may press abutton or send a command to the controller to activate dust accumulationbased filter bag cleaning. In another example, the controller mayautomatically activate dust accumulation based cleaning based on anenvironmental condition, such as air pressure, air velocity, time,temperature, humidity, etc.

When dust accumulation based cleaning is enabled, the controller inoperation 254 measures the air pressure/air velocity for a next row offilter bags as described above. For example, the controller may use thepitot tubes to measure the air pressure/air velocity for a particularfilter bag in a next row of filter bags to be passed over by thecleaning arm. The measured air pressure/air velocity indicates an amountof dust/particulate accumulation on the filter bag. In operation 256,the controller monitors the current location of the cleaning arm. Forexample, the controller receives signals from the proximity sensorsindicating when the cleaning arm is located over the next row of filterbags.

In operation 258, the controller may activate the diaphragm valve andrelease air streams from the venturis into the next row of filter bagsbased on any currently programmed cleaning pattern and/or any measuredair pressure for the row of filter bags. For example, dust accumulationbased cleaning may be disabled in operation 252. In this case, thecontroller may clean rows of filter bags based only on the cleaningpattern previously identified in operation 250.

In another example, dust accumulation based cleaning may be enabled inoperation 252. The controller may normally clean rows of filter bagsbased on the cleaning pattern identified in operation 250. However,whenever the measured air pressure/air velocity for a next row of filterbags drops below a given threshold, the controller may clean the nextrow of filter bags regardless of the programmed cleaning pattern.

In yet another example, there may not be a preprogrammed cleaningpattern and the controller may dynamically determine when to clean eachrow of filter bags based on the measured air pressure/air velocityand/or may dynamically vary the cleaning pattern used to cleansubsequent rows of filter bags based on current or previously measuredair pressures/air velocities.

In another example, over time the controller may identify dustaccumulation patterns on the filter bags. For example, based ondifferences in measured air pressure/air velocity, the controller mayidentify a specific section or group of filter bags that accumulateparticulates faster than other sections or groups of filter bags. Thecontroller may dynamically adjust the existing cleaning pattern to cleanspecific sections of filter bags more often or for longer periods oftime than the other groups or sections of filter bags.

Cleaning system 100 may be less complex and less expensive tomanufacture and operate than other baghouse cleaning systems. Forexample, only one air accumulator 140, one diaphragm valve 136, and onelinear row of venturis 144 are needed for cleaning all of the differentmultiple rows of filter bags 108. Linear actuator 148 provides a simplesingle mechanism for moving cleaning arm 112 back and forth from thefront to the rear of the baghouse. Air pressure may be maintained withinan enclosure containing actuator 148 to reduce problems and maintenanceneeded for operating actuator 148. Dust accumulation monitoring providedby pitot tubes 152 allows more energy efficient cleaning of filter bags108 while also reducing wear on filter bags 108. Proximity sensors 174and 178 allow cleaning system 100 to use any programmable pattern forcleaning filter bags 108 and in combination with air pressure monitoringby pitot tubes 152 can dynamically clean any combination of filter bagsbased on any dust accumulation or other environmental condition.

Hardware and Software

Several examples have been described above with reference to theaccompanying drawings. Various other examples are also possible andpractical. The systems and methodologies may be implemented or appliedin many different forms and should not be construed as being limited tothe examples set forth above. Some systems described above may usededicated processor systems, micro controllers, programmable logicdevices, or microprocessors that perform some or all of the operations.Some of the operations described above may be implemented in software orfirmware and other operations may be implemented in hardware.

For the sake of convenience, the operations are described as variousinterconnected functional blocks or distinct software modules. This isnot necessary, however, and there may be cases where these functionalblocks or modules are equivalently aggregated into a single logicdevice, program or operation with unclear boundaries. In any event, thefunctional blocks and software modules or features of the flexibleinterface can be implemented by themselves, or in combination with otheroperations in either hardware or software.

Digital Processors, Software and Memory Nomenclature

As explained above, embodiments of this disclosure may be implemented ina digital computing system, for example a CPU or similar processor. Morespecifically, the term “digital computing system,” can mean any systemthat includes at least one digital processor and associated memory,wherein the digital processor can execute instructions or “code” storedin that memory. (The memory may store data as well.)

A digital processor includes, but is not limited to a microprocessor,multi-core processor, Digital Signal Processor (DSP), GraphicsProcessing Unit (GPU), processor array, network processor, etc. Adigital processor (or many of them) may be embedded into an integratedcircuit. In other arrangements, one or more processors may be deployedon a circuit board (motherboard, daughter board, rack blade, etc.).Embodiments of the present disclosure may be variously implemented in avariety of systems such as those just mentioned and others that may bedeveloped in the future. In a presently preferred embodiment, thedisclosed methods may be implemented in software stored in memory,further defined below.

Digital memory, further explained below, may be integrated together witha processor, for example Random Access Memory (RAM) or FLASH memoryembedded in an integrated circuit Central Processing Unit (CPU), networkprocessor or the like. In other examples, the memory comprises aphysically separate device, such as an external disk drive, storagearray, or portable FLASH device. In such cases, the memory becomes“associated” with the digital processor when the two are operativelycoupled together, or in communication with each other, for example by anI/O port, network connection, etc. such that the processor can read afile stored on the memory. Associated memory may be “read only” bydesign (ROM) or by virtue of permission settings, or not. Other examplesinclude but are not limited to WORM, EPROM, EEPROM, FLASH, etc. Thosetechnologies often are implemented in solid state semiconductor devices.Other memories may comprise moving parts, such a conventional rotatingdisk drive. All such memories are “machine readable” in that they arereadable by a compatible digital processor. Many interfaces andprotocols for data transfers (data here includes software) betweenprocessors and memory are well known, standardized and documentedelsewhere, so they are not enumerated here.

Storage of Computer Programs

As noted, some embodiments may be implemented or embodied in computersoftware (also known as a “computer program” or “code”; we use theseterms interchangeably). Programs, or code, are most useful when storedin a digital memory that can be read by one or more digital processors.The term “computer-readable storage medium” (or alternatively,“machine-readable storage medium”) includes all of the foregoing typesof memory, as well as new technologies that may arise in the future, aslong as they are capable of storing digital information in the nature ofa computer program or other data, at least temporarily, in such a mannerthat the stored information can be “read” by an appropriate digitalprocessor. The term “computer-readable” is not intended to limit thephrase to the historical usage of “computer” to imply a completemainframe, mini-computer, desktop or even laptop computer. Rather, theterm refers to a storage medium readable by a digital processor or anydigital computing system as broadly defined above. Such media may be anyavailable media that is locally and/or remotely accessible by a computeror processor, and it includes both volatile and non-volatile media,removable and non-removable media, embedded or discrete.

Having described and illustrated a particular example system, it shouldbe apparent that other systems may be modified in arrangement and detailwithout departing from the principles described above. Claim is made toall modifications and variations coming within the spirit and scope ofthe following claims.

The invention claimed is:
 1. An apparatus, comprising: a elongated airaccumulator configured to retain pressurized air and extend over a rowof filter bags; an elongated air tube extending along the airaccumulator; venturis extending from the air tube and configured to blowair into the filter bags; and an accumulator valve fluidly coupling theair accumulator to the air tube; and an actuator configured to move theair accumulator and air tube linearly over different individual rows ofthe filter bags; wherein the air accumulator comprises a hollow beam. 2.The apparatus of claim 1, wherein the venturis extend underneathsubstantially the entire hollow beam.
 3. The apparatus of claim 2,wherein the venturis are positioned on the air tube to substantiallyalign with vertical center lines for all of the filter bags in the rowof filter bags.
 4. The apparatus of claim 1, further comprising: a shaftextending from a front end to a back end of a structure retaining thefilter bags; and a motor configured to rotate the shaft, wherein theactuator is configured to move the air accumulator linearly between afront end and a back end of the shaft in response to the motor rotatingthe shaft.
 5. The apparatus of claim 4, further comprising an enclosureattached to the air accumulator and containing the actuator.
 6. Theapparatus of claim 5, further comprising an air valve configured todirect pressurized air from the air accumulator into the enclosure. 7.The apparatus of claim 1, further comprising: a sensor configured tomeasure air pressure for air flowing up and into the filter bags; and acontroller configured to actuate the accumulator valve and causepressured air streams to flow out of the venturis and into the filterbags based on the air pressure measured by the sensor.
 8. The apparatusof claim 7, wherein the sensor comprises a first pitot tube extending infront of the air accumulator and a second pitot tube extending behindthe air accumulator.
 9. The apparatus of claim 1, further comprising:proximity sensors located proximate to associated rows of filter bags; aposition activator located proximate to a lateral side of the airaccumulator and configured to trigger the proximity sensors as the airaccumulator moves over the associated rows of filter bags.
 10. Theapparatus of claim 9, further comprising a flexible power track couplingan air supply to the air accumulator and coupling a control line to theaccumulator valve.